accufab throttle body question

archerto

New Member
Jan 18, 2006
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More than likely, it's not gunk or excess oil gumming up your TB and causing it to stick. It's vacuum lock, and it happens when your idle set screw backs off (loosens) ever so slightly. Even just 1/8 of a turn can cause this, or if any part of the end of the set screw is worn off, your tb blade will close just a little too much, causing enough vacuum that can't be overcome by the IAC alone, hence causing "vacuum lock." This is the cause of the momentary stickiness that you feel in the gas pedal when you move off idle.

I was really hesitant to mess with the idle screw until I spoke with an Accufab tech directly. The tech told me to tighten the idle screw by 1/8 turn increments until the vacuum lock is gone. I actually did it 1/4 at first but then backed it off to 1/8 of a turn and this 100% addressed my sticky throttle issue.

Make sure for good insurance that after you fix the vacuum lock you check and re-set (if necessary) the TPS, as this can cause idle and driveability problems if it's not reading in specs, which I think was between .98 and 1.0 volts. You'll need a voltmeter - it's super easy to do. I actually used two small fishhooks to pierce the TPS wires and more easily hook up my digital voltmeter. Oh yeah, definitely use a digital voltmeter and not an analog one.

Good luck and let me know if this works for you.

I found this in an earlier post and am having this same problem with my accufab sticking from vacuum lock. Where is the idle screw on the accufab located so that I can adjust it?
 
Just tried it. :( I didn't notice anything different. Still had that sticky feeling at initial tip in.

May be a I will pull the TB this weekend clean it up and put a oil seperater in.

If you want to try you will need a 3/32 allen wrench and a 3/8 open end.